The invention relates generally to the securing of objectts in passages. Of particular interest to the invention are the hose lines used in coal mines for the purpose of dust suppression, which hose lines are arranged in boreholes.
In order to suppress dust in coal mining such as, for instance, in the mining of bituminous coal, boreholes leading to sources of dust are formed and hose lines are arranged in the boreholes so that these sources may be wetted or soaked with water. It is necessary here, for the various soaking methods, that the hose lines be durably and firmly sealed in the boreholes. In the conventional, continuous soaking methods, the seal for the lines and the probes must extend over a distance of at least 15 meters in order to be able to withstand the water pressure which builds up, for example, in the coal face, during the course of the soaking procedure. This water pressure may attain values of up to 350 bars.
As a rule, the sealing of the free space between the wall of the hose line and the wall of the borehole is accomplished by means of a cement slurry. Where the borehole extends in downward direction, the cement slurry is poured into the borehole whereas, for boreholes which extend in upward direction, the cement slurry is pumped into the borehole. The cement slurry usually sets no sooner than 24 hours after being poured or pumped. It is only after setting has occurred that the soaking operation may be begun.
The long setting time of a least 24 hours required for the cement slurry makes it impossible to produce the borehole, seal the probes and hose lines and begin the soaking operation within a single shift. The loss, for soaking purposes, of the period of time corresponding to the setting period is particularly serious in those cases where the advancing longwall system is used and greatly influences the dust suppression in an adverse manner. Also, the long setting time results in relatively high labor expenditures and, consequently, in high costs.
A further disadvantage of the method outlined above resides in the fact that the seal obtained after setting or hardening is brittle. Thus, when ground movements or ground shifting occur, as is frequently the case underground, the brittle sealing mass cracks at various locations. In many instances, this leads to breaks in the seal which, in turn, often requires stoppage of the soaking procedure since the water leaks out at the broken locations and does not penetrate the source of dust such as, for instance, the coal face.
There further exists the disadvantage that lumps often form during mixing of the cement slurry and these may cause substantial disturbances in the operation when the slurry is forced into upwardly extending boreholes since the pump used for this purpose can then no longer work freely. Moreover, the production of the cement slurry in underground operations poses risks from a hygienic point of view since cement dust may be drawn along by the fresh air draft provided and may lead to skin irritations.